1. Field of the Invention
The present invention relates to a communication system capable of wireless or wired communications, and particularly to a communication system capable of switching between a wireless line and an electric power line as deemed appropriate in performing communications. In addition, the present invention relates to a communication system capable of switching between communication modes having different transmission rates in performing communications via the wireless line or the electric power line.
2. Description of the Related Art
In conventional communication systems which switch between wireless and wired lines, in order to perform wired communications, a dedicated communication line is required even under conditions where wired communications seems viable. In addition, in cases where securing a wired network such as a LAN or the like is difficult, it is necessary to continue wireless communications. Therefore, traffic in wireless communications is occupied more than is necessary for reasons such as only the wireless line being used because a wired connection cannot be established. In order to resolve such shortcomings, for example, Issued Japanese Utility Model No. 2583238 or the like is disclosed. According to the technology in this publication, a wireless transmitter and a wired transmitter are provided, and switching between wireless communication and wired communication appropriately is made possible by detecting the connection status of each transmitter. However, even with this technology, a communication line dedicated to wired communication is required, and communications using electric power lines which are versatile cannot be achieved. As such, in Issued Japanese Patent No. 2749248 or the like, an electric power line carrier system using a wireless line and an electric power line concomitantly is disclosed. According to this technology, wireless communications may be performed when a cordless handset is removed from a cradle (battery charger), while wired communications between the cordless handset and a base unit via the electric power line (i.e., a commercial power supply line) may also be performed when the cordless handset is mounted on the cradle.